Why compression strength to determined and standard practice

Use the below table to find out the compressive strength gained by concrete after a specified age in relation to the grade of concrete used.

Viewing the table, you can discover that concrete gains
Age after Casting Gains Strength in Percentage
in one day 16 % strength
in 3 days 40 % strength
in 7 days 65% strength
in 14 days 90% strength
in 28 days 99% strength.

Therefore, concrete gains strength rapidly in the first two weeks after casting (90% in just 14 days). In 28 days, the concrete’s strength will have reached 99% and continues to gain strength in the future. However, the rate of gain advances at a much-reduced pace when compared to the first 28 days.